I could be getting free gratis an MJ Ref 1 MKII subwoofer. It has been repaired once and as far as I know only the main reservoir capacitors in the main power supply have been replaced. The fault manifested as slow motorboating. A year after repair the fault has returned. I know the present owner and she definately has not been thrashing it, all controls are set at sensible settings. Is this a unique fault or has anybody else come across this form of failure?